Maybe science has come up with an answer for why many of my favorite photos capture people in motion. According to Cognitive Daily, which reports about research of human cognition, we recognize people better when they're moving. We're talking about some very small increments of time here: Within 150 milliseconds of being shown a photo, the human brain creates differing responses, depending on whether the photo contains animals or not. But the motion of the animal apparently tells us a lot as well. We are able to recognize friends and family members simply from point-light displays of them moving. I'm no scientist (believe it or not!) but I think we are hard-wired to respond to motion--action that might bring danger our way, or perhaps an athletic mate very capable of sexual reproduction. Or, in the case of Cartier-Bresson's "Behind the Gare St. Lazare," a warm laugh at the human condition. At any rate, it's worth remembering the next time you're making a portrait of someone. Make them move!